"In Russia the scenario is always the same - presidential property managers arrive at the former celebrity's dacha and ask him to vacate the premises."

It went on: "This is how the system moves against those who have fallen out with it."

'Warning'

Yevgeny Volk, head of an influential think-tank, said the Kremlin was warning Mr Berezovsky to drop his opposition to the Putin government and leave the country, like his fellow "oligarch" Vladimir Gusinsky.

"The authorities don't want those two to remain here. Their interference in Russian politics appears dangerous for the Kremlin," Mr Volk said.

Mr Berezovsky himself has accused President Putin of hounding him for political reasons.

"But I don't give into blackmail," he said.

Mr Putin has promised to restrict the political influence of the "oligarchs" and to abolish the system of crony capitalism that helped them accumulate their wealth.